High-Dynamic Range (HDR) specifications require peak brightness and dark state brightness, the actual requirements for the contrast level and contrast enhancement. Therefore, it is important to increase the contrast of the liquid crystal panel by reducing the dark state transmittance of the polarizer and increasing the polarization degree of the polarizer.
Polarizer is a multi-layer film structure, usually including the PVA layer, the compensation film, etc., affect the polarization degree of the polarizer is not only the core layer of the PVA layer, the compensation film layer will also affect the polarization degree, thus affecting the LCD panel contrast. How to sort out the impact of polarizer film is very important, and only clarify the impact of the film, in order to improve the overall structure to improve and enhance the polarization degree and panel contrast.
Commonly used LCD panel display mode is VA mode, VA display is a vertical alignment of the normally black mode, the upper and lower substrate polarizer absorption axis vertically offset. Polarizers play a crucial role throughout the display. The polarizer absorbs light in a direction perpendicular to the polarization axis and transmits only the light in the polarization axis direction to convert the natural light into linearly polarized light. Such materials are all in the form of films or plates and are therefore often referred to as polarizing films or polarizers.
The dark state brightness affected the contrast of the LCD panel greatly. Specific reference Table 1 shows:
TABLE 1the effect of the dark state brightness of the LCD on the contrastBright state400400400400400Dark state0.40.30.20.10.05Contrast10001333200040008000Contrast100%133%200%400%800%ratio
As can be seen from the table above, the effect of the dark state brightness on the contrast depends on the determinant factor. Therefore, it is important to improve the contrast of the liquid crystal panel by reducing the dark state brightness of the polarizer and increasing the polarization degree of the polarizer.
The main factors that affect the transmittance and the polarization degree of the dark state in the polarizer are the PVA layer and the compensation film. At present, the measurement is the measurement of the polarizer as a whole, and it is impossible to sort out which layer affects the dark state performance.
Therefore, in view of the above technical problem, it is necessary to provide a method of measuring optical parameters of a polarizer and a measuring device.